An improved description of the heart from surface electrocardiography will aid clinical practice; a better accounting of the surface phenomena from the heart's form and behavior will add to fundamental understanding. This proposal is to examine extensively the particular use of the equivalent multipolar generator as the bridge of information transfer between the surface in both (1) the living heart and (2) parallel anatomically and physiologically advanced models of its activation and recovery. To attain these objectives we will sustain a continued program for the systematic collection of human body surface potential maps with detailed associated clinical and anatomical data. We will utilize collected data to construct a multipolar sensitive lead system by which body surface potential map data can be obtained by a limited number of leads. We will develop the associated instrumentation to permit practical on-line recording during changing states of either activation, or recovery. Thus, we may obtain comparative characterization of activation by the moving dipole and dipolar pair, and the process of recovery by the time-course of the multipolar field (or tensor field) of the intrinsic T or ventricular gradient. Ventricular mosaic computer models of excitation and recovery which respond and correspond to the multipolar parameters will permit probabilistic correlation of both processes with time-varying surface potential patterns.